养分对入侵植物大狼耙草和近缘本地植物狼耙草竞争的影响

为探讨大狼耙草的入侵特性,采用盆栽试验,研究了不同养分条件对入侵植物大狼耙草(Bidens frondosa L.)和近缘本地植物狼耙草(B.tripartita L.)竞争的影响。结果表明,大狼耙草的竞争响应随着养分的增加而降低,而本地种狼耙草的竞争响应随着养分的增加而升高,低养分下大狼耙草的竞争响应大于狼耙草的竞争响应,高养分下则相反。低养分下,竞争显著降低大狼耙草的生长,而高养分下,竞争显著降低本地植物狼耙草的生长,说明了养分的增加提高了入侵植物大狼耙草的竞争能力,同时降低了本地植物狼耙草的竞争能力。人类活动使生境中的养分增加,会提高大狼耙草对狼耙草的竞争能力,促进其入侵。

Effects of Nutrient on Competition between Invasive Species Bidens frondosa and Native Congener B. tripartita

Bidens frondosa L. is an exotic annual herb native to North America, which often co-occurs with native congener B. tripartita L. in habitats, such as abandoned arable land, farmland etc. In order to understand the invasiveness of B. frondosa, the effects of compound fertilizer on competitive response of B. frondosa and B. tripartita were studied. The results showed that the competitive response of B. frondosa declined with nutrient increment, while that of B. tripartita increased. Furthermore, the competitive response of B. frondosa was greater than that of B. tripartita under low nutrient level and on the contrary under high nutrient level. The growth of B. frondosa was suppressed by competitor under low nutrient, while did that of B. tripartita under high nutrient. Therefore, it was suggested that the competitive ability of B. frondosa was enhanced with nutrient increasing, meanwhile that of B. tripartita decreased. Human activities cause nutrient increase, which increase the competitive capacity of B. frondosa to B. tripartita, and then improved the exotic species invasion.